C++ basic_istream::unget()用法及代码示例

basic_istream::unget()用于取出字符，并将位置减少一个字符，并使提取的字符可再次使用。头文件：

<iostream>

用法：

basic_istream& unget();

参数：basic_istream::unget()方法不接受任何参数。返回值：函数basic_istream::unget()返回basic_istream对象。下面是说明std::basic_istream::unget()：Program 1的程序：

CPP14

// C++ code for basic_istream::unget() 
#include <bits/stdc++.h> 
using namespace std; 
  
// Driver code 
int main() 
{ 
    // Declare string stream 
    istringstream gfg("GeeksforGeeks"); 
  
    char a = gfg.get(); 
    if (gfg.unget()) { 
        char b = gfg.get(); 
        cout << "We got:" << a << endl; 
        cout << "After ungetting the "
             << "character once again"
             << " we got:"
             << b << endl; 
    } 
  
    return 0; 
}

输出：

We got:G
After ungetting the character once again we got:G

程序2:

CPP14

// C++ code for basic_istream::unget() 
#include <bits/stdc++.h> 
using namespace std; 
  
// Driver code 
int main() 
{ 
    // Declare string stream 
    istringstream gfg("Laptop"); 
  
    char a = gfg.get(); 
    if (gfg.unget()) { 
        char b = gfg.get(); 
        cout << "We got:" << a << endl; 
        cout << "After ungetting the "
             << "character once again"
             << " we got:"
             << b << endl; 
    } 
  
    return 0; 
}

输出：

We got:L
After ungetting the character once again we got:L

参考：http://www.cplusplus.com/reference/istream/basic_istream/unget/

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注：本文由纯净天空筛选整理自bansal_rtk_大神的英文原创作品 basic_istream::unget() in C++ with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。